Starting apparatus for internal combustion engines



R. HAMMER sept. s, l192.8.

2,128,939 STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES v Filedoct. 2s. 1954 A2 sheets-meet 1` Sept. 6, 1938.y R. HAMMER 2,128,939

STARTING APPARATUS FOR INTERNAL COMBUSTION ENGINES y Filed oct; 2:5,v1934 l 2 sheets-sheet 2 Patented Sept. 6, 1938 UNITED STATES STARTINGAPPARATUS FOR INTERNAL COMBUSTIGN ENGINES Richard Hammer, Winnenden,Germany, assigner to Robert Bosch Gesellschaft mit beschrankterlHaftung, Stuttgart, Germany Application october 23, 1934, serial No.149,627 In Germany November 4, 1933 18 Claims.

The present invention relates to starting apparatus for internalcombustion engines, in which the pinion is connected to the drivingshaft by means of a friction clutch acting automatically through anaxially movable pressure member and can be displaced longitudinallytogether with the driving shaft or relatively to it without substantialrotation relative thereto for engagement.v

The known starters of this kind have the dis- D advantage that thetoothed rim of the fiywheel and the pinion are damaged or at leastgreatly worn if the teeth of the pinion, on engagement, impact with theteeth of the iiywheel, because when the teeth encounter each other thewhole 5 torque of the starter is transmitted to the pinion. In order toovercome this drawback, it has already been proposed in electricstarters to pro vide an auxiliary field, which during the engagement ofthe pinion can only deliver a small torque, in addition to which, afterthe engagement of the pinion, the main field which exerts `the fulltorque is put into circuit in dependence on the movement of the pinion.It has also been proposed to reverse the direction of rotation of thearmature on the engagement of the pinion bythe auxiliary field. Theseapparatus have the Vdisadvantage that troublesome appliances arenecessary to change over the field windings in dependence upon theposition of the pinion.

.0 In order to overcome all these disadvantages,

according to the invention the pinion is connected to the starter shaftby a clutch for small torque for the engagement, and by a clutch for thefull torque for starting up the motor.

:5 Four examples of construction according to the invention are shown inthel accompanying drawings, in which:

Figure 1 is a diagrammatic illustration of a starter.

L0 Figure 2 is a second form of the 'invention in longitudinal "sectionFigure 3 a section on the line 3-3 of Fig. 2. Figure 4 a. longitudinalsection of a third method of carrying out the invention.

L5 Figure 5 a section on the line 5 5 of Fig. 4.

In Figure 1, a is the armature of an electric motor, and b the armatureshaft which is borne at c and d. On the armature shaft a sleeve e isarranged so as to be rotatable and axially i0 displaceable. The end ofthe sleeve facing the bearing d is formed as a pinion f while the otherend is provided with claws or clutch teeth g. The bore of the sleeve isenlarged at this latter end to receive a friction spring h, which 55 atone end is fastened to the shaft of the armature and bears on the insideof the sleeve. i is a locking pinwhich is inserted in a radial hole ofthe sleeve and can engage in an annular groove It in the armature shaft.m is a spring which tends to draw the pin outwards.

Externally the pin bears on a fixed stop 1L connected, for instance, tothe casing of the starter, and having two steps o and p, which are soarranged that in the position of rest of the starter the pin engages inthe groove k of the armature'shaft and in the contracted position isdrawn out of the groove. On the armature shaft a friction clutch plate qis keyed. This has claws r which can engage vwith the claws g of thesleeve. s is a compression spring, which is arranged between the clutchplate q and the sleeve e, and t is the return springof the armature.

The mode of action is as followsz When the starter is switched on forstarting` the motor, the rotating armature is attracted by the poles ofthe starter and thereby also the sleeve -e displaced by the spring s androtated by the slip spring h. If the pinion engages without impact, thepin i is-drawn out of the groove k as soon as it comes below the step pof the stop n.' On further displacement, the pinion sleeve abuts againstthe projection u of the bearing d. Since the armature can now move stillfurther, the claws r on the clutch q comeinto engagement with the clawsg of the sleeve. I'he armature shaft and the sleeve are now coupledtogether by the clutch q. l

When the engine overtakes the starter, the armature is drawn back inknown manner by the spring t and the sleeve pushed back by the drivingpin v.

If tooth impacts on tooth, only the Weak friction clutch formed by thespring h is operative. A coupling of the sleeve e with the clutch plateq is hindered by the locking pin z', which in this position of thesleeve still engages in the groove k of the armature shaft and thuslocks the armature shaft relative to the sleeve. As soon as the pinionhas run itself into the spaces between the teeth of the flywheel, thesleeve lis unlocked, whereupon the further starting operation proceedsin the above described manner. The clutch for the full torque is thuscut in quite automatically.

A second method of carrying out the invenarmature shaft of an electricmotor 2. On the armature shaft a sleeve 3 is arranged so as to berotatable. The end of the sleeve situated at the Y tion is shown inFigures 2 and 3. Here, I is the end of the armature shaft is formed as apinion I. whilst at the other end ofthe sleeve a thread 5 is provided,on which a nut 6 can screw. 'I'his nut forms a part of afriction clutch1, which is to couple the armature shaft I with the sleeve.

3. The counter-part to the nut Ii is a shell I, keyed on to the armatureshaft. Between the nut andv this shell, friction discs 9 and I3 arearranged in the usual manner, which engage lnl grooves II and I2inthenut and the shell. I3 is a pressure plate for the friction discs,which plate I3 can bear against an abutment I4, and I5 is a flange ofthe nutl 6 serving as pressure mem-- ber of the clutch. One of the discsconnected with the shell, namely the disc Illa, has lugs I6 engaging inthe grooves of the shell which are extended beyond the edge of theshell. On the casing I'I of the starter is provided an annular disc I8,which forms a stop for the lugs I6 of the disc IIIa and lies on the sideof the lugs facing the pressure plate I3. In the ange I5 of the nut 6,small compression springs I9 are insertedwhich gently press thosediscswhich 4lie between the flange and the annular disc against thelatter. In the position of rest of the starter the distance a of thepressure plate I3 from thev friction discs is greater than the distance'of the pinion l from the toothed rim v2II of the flywheel of theinternal combustion engine.

The mode of action of this apparatus is as follows:

To start the internal combustion engine, the electric motor 2 isswitched on'. The armature of the motor is in known manner attractedinto the field of the motor, and thereby the pinion on the armatureshaft moved towards the toothed rim of the engine. By this displacementof the armature the whole clutch I is likewise moved. 'Ihe small springsI9 of the nut 6 press the friction discs steadily in the direction ofthe pressure i plate I3 or annular disc I8, so that thus thev discs donot follow the motion of the armature but the pressure plate I3approaches nearer and nearer to the friction discs. When the pinion hasf tance p;'fthe pinion is held fast.

travelled the distance it begins to engage with the toothed rim 20.Since the distance is smaller than the spacing a of the pressure platefrom the friction discs, these cannot come into operation until Athepinion has already to a certain extent engaged in the toothed rim of theiiywheel, i. e., the friction plates 3, I0 can only all come into actionwhen the pinion teeth are already in mesh with the flywheel teeth. thepinion is fully engaged, the'presure plate I3 has moved forward thefriction discs so far that the disc I0a no longer bears on the annulardisc I3 and therefore all the discs can be compressedV between the nutflange I5 and the pressure plate If however, pinion tooth impacts onflywheel tooth, which may occur after travelling the dis- The nut 5 isdriven by the discs lying between the flange I5 and the annular disc IBand screws itself towards the discs. As in this position the pressureplate I3 does not yet bear on the friction plates, only the discssituated between the nut iiange I5 and the annular disc I3 are pressedtogether. Since the torque transmitted by a friction disc clutch issubstantially proportional to the friction surfaces of the discs, thetorque transmitted by the few discsin the example illustrated two discs-When change from low torque to high torque takes piaci automatically.

In the third example of construction, shown in Figures 4 and 5, in whichthe same references are adopted for the same parts as in Figures 2 and3, the friction disc 25, which is preferably shaped like a pot, andbears on the flange disc I5 of the nutA i, is pressed by .a spring 26against the ange I5 of the pressure nut 6. 'I'he spring 26 bears againstan abutment 21, which is provided on the coupling shell 8. 'I'he spring26 is so chosen that its pressure is overcome by the attraction force ofthe armature, when the nut 6 bears against the bearing 28. In this casethe pressure plate I3 is moved forward so far towards the frictiondiscs, that it presses these against the flange of the nut 6, wherebyall the said discs become operative, i. e., the full torque of thearmature is transmitted.

If tooth impactsv on tooth, only the friction between the flange I5 andthe friction disc 25 is effective for the transmission of the torquefrom the armature to the pinion.

The starting apparatus according to the invention renders it possible togo to the full torque of the starter motor, before the pinion isengaged, without having to fear that in the engagement the pinion andthe toothed rim of the flywheel will be damaged.

I declare that what I claim is:

1. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion, driving means connected with said driving shaftand rotating the same before and after said pinion is in mesh with atoothed member of the engine, friction clutch means, in constantengagement, adapted to transmit only a'low torque from said shaft to thepinion, friction clutch means adapted to transmit the full torque of thedriving means to the pinion and means for always automatically bringing4said second-mentioned clutch means vinto operation after the pinion isin mesh with the toothed member of the engine but preventing said secondmentioned clutch means from coming into operation until the pinion is inmesh with said member.

2. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion adapted to mesh with a toothed member of theengine to be started, driving means connected with said driving shaftand rotating the same before and after said pinion is in mesh with saidtoothed member, friction clutch means, in constant engagement betweensaid driving shaft and said pinion and means permitting operation ofaportion only of said clutch means to transmit a low torque only duringmeshing of the pinion with said toothed member and for bringing intooperation the remainder of said clutch means only after meshing of thepinion.

3. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion adapted to mesh with a toothed member of theengine to be started, driving means connected with said driving shaftand rotating the same before and after said pinion is in mesh with saidtoothed member, friction clutch means including friction discs, aportion of which are in constant engagement, between said driving shaftand said pinion and means permitting operation of a. portion only ofsaid friction discs 1to transmit a low torque only during meshing of the.pinion with said toothed member and for bringing into operation theremainder of the friction discs only after meshing of the pinion.

4. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion, driving means connected with. said drivingshaft, friction clutch means includingtriction discs between saiddriving shaft and pinion adapted to transmit the whole torque of thedriving means to the pinion, pressure members at opposite ends of saidfriction discs and a fixed stop intermediate of said pressure membersand means cooperto the pinion, pressure members'at opposite endsv ofsaid friction discs and a fixed stop intermediate of said pressuremembers and means cooperating therewith and with said pressure membersadapted to bring into 'operation only those friction discs locatedbetween itself and one of said pressure members during engagement of thepinion. Y

6. Starting apparatus for internal combustion i engines comprising adriving shaft, a pinion,

driving means connected with said driving shaft,

friction clutch means between said driving shaft and pinion including'friction discs, a Adriving clutch member and a driven clutch member,one of said discs connected with the driving clutch 'member having aprojection extending externally 1 of the drivingclutch member and a-xedstop adapted.l for engagement with said friction disc having saidprojection and means cooperating I therewith to causev this disc aloneto come into operation during engagement of the pinion.

'7. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion, driving means connected with said drivingshaft, friction clutch means including friction discs between saiddriving shaft and pinion adapted to transmit the whole torque of thedriving means to the pinion, pressure members at opposite ends of saidfriction discs, a fixed stop intermediate of said pressure membersadapted to bring into operation only those friction discs locatedbetween itself and one of said pressure members during engagement of thepinion and springs between said pressure member and said discs formaintaining said discs in engagement with the stopv during engagement ofthe pinion.

8. Starting apparatus for internal combustion .engines comprising adriving shaft, a pinion,

driving means connected with saig driving shaft, friction clutch meansbetween saiordriving shaft and said pinion including friction membersassociated with the driving shaft and the pinion respectively and meansincluding opposed pressure members associated with the driving shaft andpinion respectively and a spring. abutting at one end against one ofsaid pressure members and abutting at the other end against one of thefriction members associated with the driving y shaft to press the sametowards the other pressure member.

9. Starting apparatus for internal combustion engines comprising adriving shaft, a pinion, driving means connected with said drivingshaft,

friction clutch means between said driving shaft and said pinionincluding friction members associated with the driving shaft and thepinion respectively and means including opposed pres,- sure membersassociated with the driving shaft and pinion lrespectively and a springabutting at one end against one of said pressure members and abutting atthe other end against one of the and abutting at the other end againstone of the friction members associated with the driving shaft to pressthe same directly against the other pressure member which is associatedwith the pinion.

11. Starting apparatus for internal combustion engines comprising a`driving shaft, a pinion, driving means connected with said driving shaftand rotating the same before and after said pinion is in meshwithatoothed member of the engine, friction clutch means between saiddriving shaft and said pinion including friction discs associated withthe driving shaft and thel pinion respectively, resilient means forpressing` certain of said friction discs togetherv to transmit a lowtorque from the driving shaft to the pinion during engagement of thepinion and means including a pressure member for causing engagement ofall of said discs to transmit a-high torque after such engagement of thepinion and operable to always prevent engagement of all of said discsuntil the pinion is in mesh with said toothed member.

12. Starting apparatus -for internal combustion engines comprising avdriving shaft, means for driving said shaft, a pinion, a multiple-discclutch between said driving shaft and pinion, and means including anautomatically acting pressure member and an abutment cooperatingtherewith operable to permit engagement of only a portion of the clutchdiscs during engagement of the pinion and to permit engagement of all ofthe clutch discs after engagement of said pinion.

13. Starting apparatusfor internal combustion engines comprising adriving shaft; a pinion, driving means connected with said drivingshaft, friction clutch means including a portion subv stantially inengagement between said driving -secured against rotation on said sleeveand adapt- .ed to engage a member of the engine to be started,

a control member mounted on .said sleeve for longitudinal movementthereof and rotary movement therewith, and friction clutch means be--tween said shaft and said control member comprising a high-torquefriction clutch and a lowtorque friction clutch, said control membercontrolling the operation of said high-torque clutch,

and means cooperating with said control member means for impartinglongitudinal and rotaryf movement to said shaft, a. driving memberrotatably mounted on said shaftand longitudinally movabletherewithadapted to engage a member .of the engine to be started, a controlmember mounted on said driving member for longitudinal movement thereofand rotary movement therewith, a high-torque friction clutch and alowtorque friction clutch between said. shaft and saidcontrol member,said control member controlling the operation of said high-torqueclutch, and

`means cooperating with said control member for preventingoperation ofSaidhigh-torque clutch until after engagementof said driving member withsaid engine.

16. Starting apparatus for internal combustion engines comprising arotatable shaft mounted for longitudinal and rotary movements, drivingmeans for imparting longitudinal and rotaryA movement to said shaft, asleeve rotatably mounted on said shaft and longitudinally movyabletherewith, a pinion secured against rotation on said sleeve and adaptedto mesh with a member of the engine to be started, a nut threaded uponsaid sleeve for longitudinal movement thereof and rotary movementtherewith, a hightorque friction clutch and a low torque friction 7clutch between said shaft and said nut, said nut controlling theoperation of said high-torque clutch, and means cooperating with saidnut for preventing operation of said high-torque clutch until saidpinion is in mesh with said engine member.

17. Starting apparatus for internal combustion engines comprising arotatable shaft mounted for longitudinal and rotary movements. driving vbetween said shaft and control member and tension controlled by thelatter, a second friction clutch of less #folique-transmitting capacitythan sai(I main clutch alsol interposed between said shaft and saidcontrol member, and means cooperating with said control member forpreventing operation of said.main clutch until after engagement of saiddriving member with said engine.

18. Starting apparatus for internal combustion engines comprising arotatable shaft mounted for longitudinal and rotary movements, drivingmeans for imparting longitudinal and rotary movement to said shaft, adriving member rotatably mounted on said shaft and longitudinallymovable therewith adapted to engage a member of the engine to bestarted, a control member `mounted on said driving member forlongitudinal only of said clutch means into operation to transmit a low`torque during engagement of said driving member with said engine andfor bringing into operation the remainder of said clutch means afterengagement of said driving member with the engine. v

RICHARD HAMMER.

